Base-catalyzed condensation of a coordinated amine and a nitrile to form a tridentate amidine [Co(en)(NH2CH2CH2NC(NH2)CH2NH2)X]2+ (X = Cl, Br), and the subsequent hydrolysis of halide
Base-catalyzed condensation of a coordinated amine and a nitrile to form a tridentate amidine [Co(en)(NH2CH2CH2NC(NH2)CH2NH2)X]2+ (X = Cl, Br), and the subsequent hydrolysis of halide
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碱催化配位胺和腈缩合形成三齿脒 [Co(en)(NH2CH2CH2NC(NH2)CH2NH2)X]2 (X = Cl, Br)，随后卤化物水解
DOI：
10.1002/chin.198234270
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
A. Zanella
中科院分区：
文献类型：
--
作者：
D. Buckingham;C. Clark;B. Foxman;G. Gainsford;A. Sargeson;M. Wein;A. Zanella
脱质子的胺官能团在r á-[Co（en）2（NH 2CH 2CN）X] 2+离子（X= Cl，Br）中反式缩合为卤化物，导致三齿脒[Co（NH 2CH 2CH 2NC（NH 2）CH 2NH 2）（en）X] 2+的快速形成。在25 ℃下，k_（1-x）=（9.6±0.3）× 103mol ~（-1）dm ~ 3s ~（-1）（X= Cl），（1.5±0.1）× 104mol ~（-1）dm ~ 3s ~（-1）（X= Br）。0 C和μ= 1.0（NaCl 104），并完全保留有关金属中心的配置获得。A（+）546-[Co（NH_2CH_2CH_2NC（NH_2）CH_2NH_2）（en）Cl] Cl_2·H_2O的晶体结构（P_2，2I_21> 2811反射，R= 0.049）表明脒的“弯曲”构型。随后卤化物的水解遵循速率定律-d [Co]/dt=（fc，[OH-]+ fc 2K [OH-] 2）/（1 + K [OH-]）[Co]，其中k1 = 0.88 mol-1dm 3s-1，k2= 0.14 mol-1dm 3s-1，并且K= 4.5 mol-1dm 3（X= Cl）和k1 = 4.40 mol-1dm 3s-1，k2 = 0.90 mol-1 dm 3 s-1，在25.0 ℃时K= 6.7 mol-1 dm 3（X= Br），μ= 1.0（NaCl 104），其中K解释为脒部分的酸度常数。kY和k2路径中的每一个产生两种产物，第一种（1）具有与起始络合物相同的构型（完全保留光学性质），第二种（2）具有脒基团的“平面”构型，其光学构型围绕金属反转。对于X= Cl和X= Br，ki路径产生51± 2%1和49± 3%2，k2路径产生70± 2%1和30± 2%2。2-C1的结构由[Co（NH 2CH 2CH 2NC（NH 2）CH 2NH 2）Cl] ZnCl 4（Cc，2131反射，R= 0.049）上的晶体结构确定。应变能最小化计算证实2比1更稳定，剩余的未观察到的构型异构体3是最不稳定的。2-C1的碱水解遵循速率定律-d [Co]/dz= L2 [OH '][Co]，k2= 26.7±0.5 mol-1 dm ~ 3·s ~（-1），μ= 1.0（NaClO_4），产物为2-OH，光学构型完全保留。
The condensation of the deprotonated amine function trans to halide in the rá-[Co (en) 2 (NH2CH2CN) X] 2+ ions (X= Cl, Br) results in the rapid formation of the tridentate amidine [Co (NH2CH2CH2NC (NH2) CH2NH2)(en) X] 2+. Therate law takes the form-d [Co]/df= fcAm [Co][OH'] with k^=(9.6±0.3) X 103 mol" 1 dm3 s" 1 (X= Cl),(1.5±0.1) X 104 mol" 1 dm3 s" 1 (X= Br) at25. 0 C and µ= 1.0 (NaC104), and full retention of configuration about the metal center obtains. A crystalstructure of A (+) 546-[Co (NH2CH2CH2NC (NH2) CH2NH2)(en) Cl] Cl2-H20 (P2, 2I21> 2811 reflections, R= 0.049) demonstrates a “bent" configuration of the amidine. Subsequent hydrolysis of halide follows the rate law-d [Co]/dt=(fc,[OH"]+ fc2K [OH"] 2)/(l+ K [OH"])[Co] with fc,= 0.88 mol" 1 dm3 s" 1, k2= 0.14 mol" 1 dm3 s" 1, and K= 4.5 mol" 1 dm3 (X= Cl) and k\= 4.40 mol" 1 dm3s'1, k2— 0.90 mol" 1 dm3 s'1, and K= 6.7 mol" 1 dm3 (X= Br) at 25.0 C and µ= 1.0 (NaC104), where K is interpreted as the acidity constant of the amidine moiety. Two products result from each of the kY and k2 paths, the first (1) having the same configuration as the starting complex (with full retention of optical properties) and the second (2) having a “planar” configuration of the amidine grouping with inversion of optical configuration about the metal. The ki path produces 51±2% 1 and 49±3% 2 andthe k2 path 70±2% 1 and 30±2% 2 for both X= Cl and X= Br. The structure of 2-C1 is established by a crystal structure on [Co (NH2CH2CH2NC (NH2) CH2NH2) Cl] ZnCl4 (Cc, 2131 reflections, R= 0.049). Strain energy minimization calculations confirm that 2 ismore stable than 1 and that the remaining unobserved configurational isomer 3 is least stable. Base hydrolysis of 2-C1 follows the rate law-d [Co]/dz= L2 [OH'][Co] with k2= 26.7±0.5 mol" 1 dm3 s" 1 at 25.0 C, µ= 1.0 (NaC104); 2-OH is theonly product, and full retention of optical configuration obtains.